Method and machine for producing a nonwoven fabric with reduction of displacement speed of the compacted mat

ABSTRACT

The invention concerns a machine for producing a nonwoven fabric comprising a conveyor for transmitting a mat to means designed to compact same in thickness and means designed to reduce the speed of the web while it is being compacted, by the compacting means, thereby obtaining an enhanced ratio of properties lengthwise relative to crosswise properties.

The present invention relates to the methods and machines for theproduction of a nonwoven fabric consisting of fibers or of filamentscomposed of an organic material, in particular of natural, synthetic orartificial textile fibers or filaments. The fibers or filaments may becomposed, in particular, of polypropylene, of polyester or of anotherplastic or their mixtures.

A method for producing a nonwoven fabric is already known, in which amat of filaments or of fibers which is in displacement is compacted inthe direction of thickness at a compacting station. Compacting isobtained by causing the mat to pass in displacement through the nipbetween two moveable elements which are displaced in the same direction.One of the moveable elements may be a conveyor or a cylinder and theother may likewise be a conveyor or a cylinder. Downstream of thecompacting station, the compacted mat is consolidated into aconsolidated mat at a consolidation station. Consolidation may becarried out by means of mechanical needling or by means of chemical orthermal binding. Hydraulic binding by means of water jets is preferablyused.

The U.S. Pat. No. 4,632,685 describes a method for producing a nonwovenfabric, in which the two faces of the mat are displaced at first equalspeeds in a pair of conveyors and then at second equal speeds, butdifferent from the first speeds, in a second pair of conveyors. Transferof the mat from one pair to the other presents problems of structurecontrol which are all the more serious because the speed is high. Thereduction in speed takes place at a point on the path of displacement ofthe mat other than where the mat is compacted.

The nonwoven fabrics obtained have a ratio of a property in the lengthdirection, in particular of the tensile strength, to the same propertyin the breadth direction which is much greater than one. The lengthdirection is defined by the direction in which the mat is displaced whenit is delivered to the compacting station, while the breadth directionis the direction perpendicular to this direction in the plane of themat. In order to make many industrial treatments easier and improve thecharacteristics of many products, it would desirable to reduce the ratioof a property of a nonwoven fabric in the length direction to thisproperty in the breadth direction, whereas the methods for theproduction of webs, of sheets and of mats preferably orient the fibersor filaments in the length direction, while at the same time having ahigh displacement speed synonymous with high productivity.

The invention provides for this by means of a method for producing anonwoven fabric, in which a mat of filaments or of fibers which is indisplacement, said filaments or fibers being composed of an organicmaterial, is compacted in the direction of thickness at a point on itspath of displacement at a compacting station, and then the compacted matis consolidated into a consolidated mat at a consolidation stationdownstream of the compacting station in the direction of displacement ofthe mat. According to the invention, the displacement speed of the matis reduced at the very point on its path of displacement where it iscompacted.

By the mat being simultaneously compacted and reduced in displacementspeed at the same point, the fibers or filaments which, owing to thecompacting, cannot be displaced perpendicularly to the plane of the matare forced to reorient themselves in the breadth direction.

Good results were obtained by reducing the displacement speed, which ispreferably between 10 and 600 m/min, preferably from 50 to 300 m/min, ofthe mat at the compacting point by 5 to 50%, preferably by 5 to 30%.Below 5%, the speed reduction is scarcely sufficient to reduceappreciably the ratio of the tensile strength in the length direction tothe tensile strength in the breadth direction. Beyond 50%, thereorientation is so great that the uniformity of the mat is affected byit. Likewise, it is preferable to reduce the thickness of the mat at thecompacting point from 99% to 30%, preferably from 99% to 50%, whichgives the best results for the reduction in the ratio of the tensilestrength in the length direction to the tensile strength in the breadthdirection.

The property, the ratio of which is modified in the method according tothe invention, is preferably the maximum tearing tensile strength, butit is also the tensile elongation or another tensile property. It wasalso found that the method according to the invention makes it possibleto improve the delamination resistance of nonwoven fabrics.

According to an embodiment which much improves the method according tothe invention, the mat is wetted at the compacting station or justdownstream of this station. By means of this wetting, the deformation ofthe fibers of the mat is fixed, and the ratio between the property ofthe nonwoven fabric in the length direction and the property of thenonwoven fabric in the breadth direction is thus preserved, this beingobtained at the compacting station, at the exit of the latter, whereas,without fixing by wetting, the fibers tend, after no longer beingcompacted, at least partially to resume their initial orientation. Theterm “just downstream” is understood, in particular, to mean thatwetting takes place before the arrival of the mat at the consolidationstation. For example, the mat may be wetted with the aid of a hydraulicinjector arranged in such a way that the jets extend substantially overthe entire width of the mat, jets, the pressure of which is between 1and 50 bar, being delivered. Depending on the pressure used, thisfixation may already have some consolidation effect, that is to say someeffect of entanglement of the fibers. In some cases, wetting is carriedout with the aid of a liquid other than pure water.

It is also possible, instead of or in addition to wetting the mat at thecompacting station, to maintain it at the exit of the compacting stationuntil it arrives at the consolidation station, or simply over part ofthe path between the two stations, for example by using a vacuum laidonto a cylinder or onto a conveyor.

The compacted mat is subsequently consolidated into a consolidated matat the consolidation station, which, in the direction of displacement ofthe mat, is downstream of the compacting station and downstream of thepoint where, if appropriate, the wetting of the mat takes place.Consolidation may be carried out by any known means, in particular bymechanical needling with the aid of metal needles, by chemical binding,by thermal binding using thermofusible fibers and with the aid ofimpregnation means, such as a padding mangle or spraying or sprayingwith foam together with a binder. However, it is preferable by far tocarry out consolidation by hydraulic binding by means of water jets,this being combined, moreover, if appropriate, with other binding means.Hydraulic binding may be carried out by means of water jets with adiameter of between 50 and 250 microns under pressures of between 10 and1000 bar.

The mat is preferably a mat of filaments coming from a machine inhot-melt operation or a mat of fibers coming from a nonwoven card; itmay also come from a machine operating by air, known as air-laidoperation, or from a tenter-lapper.

The invention applies particularly to masses per unit area of 0 to 500g/m², preferably of 20 to 300 g/m², of the mat.

The invention makes it possible, in particular, to manufacturefiltration products, geotextiles or agrotextiles in civil engineeringand building, in motor vehicles, furnishing and clothing, in medicalapplications, and in roof seals, acoustic and thermal insulationproducts, and dry or impregnated wiping products for domestic andhygienic use.

The invention is also aimed at a machine for producing a nonwovenfabric, comprising a first element for delivering a mat to meansintended for compacting it in the direction of thickness, characterizedin that said means are also means intended for reducing the displacementspeed of the mat at the point where it is compacted by the compactingmeans. The first element is preferably a conveyor, but this may also bea cylinder fed by a conveyor.

The compacting means are implemented by the formation of a nipping pointbetween the first element and another moveable element, and thereduction in displacement speed of the mat is implemented by impartingto the other moveable element a linear speed lower than that of thefirst element. The other moveable element may be a second conveyor or asecond cylinder. Nipping preferably extends over the entire width of themat and involves an entire generatrix of the nipping cylinder.

Preferably, the machine comprises means intended for wetting the matwhen it is compacted or when it has just been compacted and before itarrives at consolidation means. Preferably, the consolidation means arearranged so as to consolidate the mat when it passes over the othermoveable element, since consolidation is all the better, the lower thepassage speed of the mat at the consolidation station is.

The invention is aimed, finally, at the use of a method or of a machineaccording to the invention for reducing the ratio of a property of anonwoven fabric in the length direction to this property in the breadthdirection and, more particularly, for reducing the ratio of the tearingtensile strength of a nonwoven fabric in the length direction to thistearing tensile strength in the breadth direction.

In the accompanying drawings, FIGS. 1 to 4 are side views of fourmachines according to the invention.

The machine illustrated in FIG. 1 comprises a conveyor comprising astand 1 resting on the ground S by means of four feet 2. This standcarries three return rollers 3, a tensioning roller 4 and a roller 5 forguiding a water-permeable belt 6 of the conveyor. Above the upper strand7 of the conveyor is mounted a cylinder 8 having a horizontal axisperpendicular to the direction of displacement of the strand 7, while awetting injector 9 is mounted vertically in line with the cylinder 8 andbelow the strand 7. The distance between the strand 7 and the lowestpoint of the cylinder 8 is so small that, when a mat is conveyed andpasses over the strand 7, it enters the nip between the strand 7 and thecylinder 8 and is compacted. The mat subsequently passes along thecylinder 8 in order to arrive in front of two injectors 10 forconsolidation by means of water jets. The cylinder 8 is a hollowcylinder which rotates counterclockwise, while the mat which passes overthe strand 7 goes from left to right in the drawing. The cylinder 8comprises a quadrant 8 a between 4 o'clock and 6 o'clock, which issubjected to a vacuum in such a way that mat is laid onto the cylinder 8from the nip exit to the injectors 10.

In FIG. 2, the machine illustrated is preferred when the thickness ofthe mat is greater than 50 mm. It comprises the same elements as themachine in FIG. 1, but, in addition, an additional conveyor carried byfour feet 11 and brackets 12. The conveyor has a guide roller 13, atensioning roller 14 and a return roller 15, and the water-permeablebelt 15 of the conveyor passes around the cylinder 8 and into the nipbetween the cylinder 8 and the belt 7.

The machine illustrated in FIG. 3 comprises, like that of FIGS. 1 and 2,a first conveyor 1 to 7 which is identical to the conveyor of FIG. 1,except that it comprises a roller 17 supporting the upper strand 7 ofthe belt.

Above this strand 7 is arranged a conveyor 18 having return rollers 19,a tensioning roller 20 and a guide roller 21, the conveyor having,furthermore, a return roller 22 which is in contact with the upperstrand 7 of the belt of the first conveyor and which is arranged on thisstrand, upstream of an injector 23 making it possible to wet a mat whicharrives on the belt 7, going from left to right in the figure. Theroller 17 is just downstream of the injector 23 and is arranged in sucha way, with respect to the roller 22, that it keeps the strand 7 inclose contact with the lower strand of the belt 24 which passes over theupper conveyor, at the same time rotating in the counterclockwisedirection. The mat is thus compressed between the upper strand 7 and thelower strand of the belt 24, is wetted at the wetting point 23 andsubsequently goes to a preliminary station 25 for consolidation by meansof water jets, before being consolidated to a greater extent on thecylinder 8 by means of the water-jet devices 10.

In FIG. 4, the ground has resting on it, by means of feet 27, a conveyor28 having a return roller 29, a tensioning roller 30 and a roller 31 forguiding a water-permeable belt 32 which is wound onto a hollow cylinder33, opposite which are mounted devices 34 for consolidation by means ofwater jets. Another conveyor 35, carried by supports 36 and brackets 37,comprises, on a stand, three return rollers 38, a tensioning roller 39and a guide roller 40. The conveyor carries a device 41 for waterprojection which will serve for wetting. This water projection device isvertically above the vertex of the cylinder 33. The mat arrives on theupper strand of the belt 32 from left to right in the figure, passesbetween the cylinder 33 and the lower strand of the belt 42 of the upperconveyor, where it is compressed, while at the same time being moistenedby the device 41, reemerges along the cylinder 33, in order to beconsolidated by means of the consolidation devices 34, and then goes toa cylinder 43 cooperating with additional consolidation devices 44.

The following examples illustrate the invention.

In these examples, the following tests were conducted:

a) Strength and Elongation in the Length Direction and in the BreadthDirection:

A sample is conditioned for 24 hours, and the test is conducted at 23°C. and at a relative humidity of 50%. A dynamometer is used for thetest, comprising a set of fixed jaws and a set of moveable jawsdisplaced at a constant speed. The jaws of the dynamometer have a usefulwidth of 50 mm. The dynamometer is equipped with a recorder which makesit possible to trace the curve of the tensile force as a function of theelongation. 5 samples of 50 mm, plus or minus 0.5 mm of width, and witha length of 250 mm are cut in the length direction and in the breadthdirection of the nonwoven fabric. The samples are tested one by one at aconstant tensile speed of 100 mm per minute and with an initial jawspacing of 200 mm. The dynamometer records the curve of the tensileforce in Newtons as a function of elongation. The maximum is determinedfrom this.

b) Mass per Square Meter:

A sample is conditioned for 24 hours, and the test is conducted at 23°C. and at a relative humidity of 50%.

At least three samples with an area of at least 50,000 mm² are cut bymeans of a cutting appliance called a guillotine.

Each sample is weighed on a laboratory balance having an accuracy of0.1% of the mass of the weighed samples.

EXAMPLE 1 (COMPARATIVE)

A mat of approximately 50 g/m² composed of 100% polyester fibers of 1.7dtex and with a length of 38 mm is produced at a speed of 50 m/min bymeans of a card of the nonwoven fabric card type.

This mat is delivered continuously to a transport and compactingconveyor of a water-jet binding installation according to FIG. 1. Thetransport conveyor is a polyester cloth with a permeability of 800 CFM.The transport conveyor has a linear speed of 50 m/min.

The transport conveyor is in contact with the cylinder over a length of10 nm. The speed of the cylinder is synchronized with the speed of thetransport conveyor to a linear speed of 50 m/min. The fiber mat iscompacted between the transport conveyor and the binding cylindercovered with a microperforated blanket, the holes being arrangedrandomly, as described in French patent 2 734 285. Immediately aftercompacting, the web is wetted and slightly consolidated by means of ahydraulic injector projecting water jets with a diameter of 140 micronsat a speed of 54 m/s under a pressure of 15 bar. The jets are spacedfrom one another at a distance of 0.8 mm in two rows.

The web, thus compacted and wetted and slightly consolidated, is thensubjected to the action of two successive hydraulic injectors projectingwater jets with a diameter of 120 microns at increasing speeds of 100m/s and 133 m/s, the jets being spaced from one another at 1.2 mm in tworows.

The nonwoven fabric thus obtained is subsequently transferred onto asuction belt connected to a vacuum generator and is then dried at atemperature of 110° C. in a flow-type air furnace.

A nonwoven fabric weighting approximately 50 g/m² is obtained. Thenonwoven fabric has a regular and uniform appearance.

EXAMPLE 2

The conditions of example 1 are repeated. For this test, the speed ofthe cylinder is reduced by 10% in relation to the speed of the conveyor.That is to say, the speed of the transport and compacting conveyor isstill 50 m/min, and the speed of the cylinder is 45 m/min.

The nonwoven fabric has a regular appearance.

EXAMPLE 3

The conditions of example 1 are repeated. For this test, the speed ofthe cylinder is reduced by 20% in relation to the speed of the conveyor.That is to say, the speed of the transport and compacting conveyor isstill 50 m/min, and the speed of the cylinder is 40 m/min.

The nonwoven fabric is regular.

EXAMPLE 4

The conditions of example 1 are repeated. For this test, the speed ofthe cylinder is reduced by 25% in relation to the speed of the conveyor.That is to say, the speed of the transport and compacting conveyor isstill 50 m/min, and the speed of the cylinder is 40 m/min.

The nonwoven fabric is irregular and has fiber wavelets in the breadthdirection.

EXAMPLE 5

The conditions of example 1 are repeated. For this test, the transportconveyor is no longer in contact with the cylinder. It is now tangent tothe latter and at a distance from the cylinder of approximately 1 mm.This new setting is obtained by lowering the return roller of theconveyor immediately downstream of the tangent point of the conveyorwith respect to the cylinder. The speed conditions are identical toexample 2, in which the speed of the conveyor is 50 m/min and the speedof the cylinder is 45 m/min.

The nonwoven fabric is regular.

EXAMPLE 6

The conditions of example 5 are repeated. For this test, the speed ofthe cylinder is reduced by 20% in relation to the speed of the conveyor.That is to say, the speed of the transport and compacting conveyor isstill 50 m/min, and the speed of the cylinder is 40 m/min.

The nonwoven fabric is regular.

EXAMPLE 7

The conditions of example 5 are repeated. For this test, the speed ofthe cylinder is reduced by 30% in relation to the speed of the conveyor.That is to say, the speed of the transport and compacting conveyor isstill 50 m/min, and the speed of the cylinder is 35 m/min.

The nonwoven fabric is regular.

EXAMPLE 8

The conditions of example 5 are repeated. For this test, the speed ofthe cylinder is reduced by 40% in relation to the speed of the conveyor.That is to say, the speed of the transport and compacting conveyor isstill 50 m/min, and the speed of the cylinder is 30 m/min.

The nonwoven fabric has surface irregularities, wavelets oriented in thebreadth direction of the mat and irregularity in its opacity.

EXAMPLE 9 (COMPARATIVE)

A mat of approximately 90 g/m², composed of 65% viscose fibers of 1.7dtex and with a length of 40 mm and of 35% polyester fibers of 1.7 dtexand with a length of 38 mm, is produced at a speed of 25 m/min by meansof a card of the nonwoven fabric card type.

This mat is delivered continuously to a transport and compactingconveyor of a water-jet binding installation according to FIG. 2. Theinstallation differs from that of FIG. 1 in the addition of an upperconveyor winding around the cylinder.

The transport conveyor is a polyester cloth with a permeability ofapproximately 800 CFM. The transport conveyor has a linear speed of 30m/min. The upper conveyor winding around the cylinder is also apolyester cloth with a permeability of approximately 500 CFM.

The transport conveyor is tangent to the second conveyor and to thecylinder and is at a distance from the second conveyor of approximately1.5 mm at the point of convergence.

The speed of the upper conveyor and of the cylinder is synchronized withthe speed of the transport conveyor to a speed of 25 m/min. The fibermat is compacted progressively between the two conveyors, and,immediately after compacting, the web is wetted and slightlyconsolidated by means of a hydraulic injector projecting water jets witha diameter of 140 microns at a speed of 63 m/s, under a pressure of 20bar. The jets are spaced from one another at a distance of 0.8 mm in tworows.

The web, thus compacted and wetted and slightly consolidated, is thensubjected to the action of two successive hydraulic injectors projectingwater jets with a diameter of 120 microns at increasing speeds of 125m/s and 160 m/s, the jets being spaced from one another by 1.2 mm in tworows.

The nonwoven fabric thus obtained is subsequently transferred onto asuction belt connected to a vacuum generator and is then dried at atemperature of 110° C. in a flow-type air furnace.

The nonwoven fabric thus obtained is regular and uniform.

EXAMPLE 10

The conditions of example 9 are repeated. For this test, the speed ofthe upper conveyor and of the cylinder is reduced by 20% in relation tothe speed of the conveyor. That is to say, the speed of the transportand compacting conveyor is still 25 m/min, and the speed of the cylinderis 20 m/min.

The nonwoven fabric is regular.

EXAMPLE 11

The conditions of example 9 are repeated. For this test, the speed ofthe upper conveyor and of the cylinder is reduced by 30% in relation tothe speed of the conveyor. That is to say, the speed of the transportand compacting conveyor is still 25 m/min, and the speed of the cylinderis 17.5 m/min.

The nonwoven fabric is regular.

EXAMPLE 12

The conditions of example 9 are repeated. For this test, the speed ofthe upper conveyor and of the cylinder is reduced by 40% in relation tothe speed of the conveyor. That is to say, the speed of the transportand compacting conveyor is still 25 m/min, and the speed of the cylinderis 17.5 m/min.

The nonwoven fabric is slightly irregular with a variation in itsopacity which suggests a slipping of fibers in the transverse direction.

EXAMPLE 13 (COMPARATIVE)

A mat of approximately 60 g/m², composed of 80% polyester fibers of 1.7dtex and with a length of 38 mm and of 20% polyester/polyethylenebicomponent fibers, as they are referred to, of 3 dtex and with a lengthof 38 mm, is produced at a speed of 30 m/min by means of a card of thenonwoven fabric card type.

This mat is delivered continuously to a transport and compactingconveyor XX of a water-jet binding installation according to FIG. 1. Thetransport conveyor is a polyester cloth. The transport conveyor has alinear speed of 30 m/min.

The transport conveyor is tangent to a cylinder. The speed of thecylinder is synchronized with the speed of the transport conveyor to aspeed of 30 m/min. The fiber mat is compacted between the transportconveyor and the binding cylinder covered with a microperforatedblanket, the holes being arranged randomly, as described in Frenchpatent 2 734 285. Immediately after compacting, the web is wetted andslightly consolidated by means of a hydraulic injector projecting waterjets with a diameter of 140 microns at a pressure of 70 bar. The jetsare spaced from one another by a distance of 1.2 mm in two rows.

The web, thus compacted and wetted and slightly consolidated, issubsequently transferred onto a suction belt connected to a vacuumgenerator and is then dried at a temperature of 130° C. in a flow-typeair furnace.

A nonwoven fabric weighing approximately 60 g/m² is obtained. Thenonwoven fabric has a regular and uniform appearance and it is bulky.

EXAMPLE 14

The conditions of example 9 are repeated. For this test, the speed ofthe upper conveyor and of the cylinder is reduced by 30% in relation tothe speed of the conveyor. That is to say, the speed of the transportand compacting conveyor is still 30 m/min, and the speed of the cylinderis 21 m/min.

The nonwoven fabric is regular and bulky.

The laboratory tests for measuring the mass per unit area and thestrength in the length direction and in the breadth direction areconducted according to the ERT standards of the EDANA.

The following table summarizes the results of strength in the lengthdirection and breadth direction and of the ratio of the length directionto the breadth direction which were obtained for each example.

Strength in Strength in Ratio of length length breadth direction to Massper unit direction direction breadth Example area g/m² N/50 mm N/50 mmdirection 1 50 136 38 3.6 2 52 139 41 3.4 3 55 145 44 3.3 4 58 155 493.2 5 55 149 45 3.3 6 59 148 50 3.0 7 63 158 61 2.6 8 65 164 66 2.5 9 9098 32 3.1 10 105 105 41 2.6 11 114 110 48 2.3 12 120 113 52 2.2 13 65 5718 3.2 14 81 64 28 2.3

1. A method for producing a nonwoven fabric, in which a mat of filamentsor of fibers which is in displacement, said filaments or fibers beingcomposed of an organic material, is compacted in the direction ofthickness at a point on its path of displacement, and the compacted matis then consolidated into a consolidated mat, downstream at aconsolidation station, characterized in that the displacement speed ofthe mat is reduced at the very point on its path of displacement whereit is compacted and the mat is maintained by applying a vacuum to itbetween the point where it is compacted and the consolidation station.2. The method as claimed in claim 1, characterized in that thedisplacement speed of the mat is reduced by 5 to 50%.
 3. The method asclaimed in claim 1, characterized in that the thickness of the mat atcompacting is reduced from 99% to 30%.
 4. The method as claimed in claim1, characterized in that the mat is wetted at compacting or justdownstream of compacting.
 5. The method as claimed in claim 1,characterized in that the mat is consolidated by causing it to passthrough the consolidation station at the reduced speed.
 6. The method asclaimed in claim 1, characterized in that the mat is consolidated byhydraulic entanglement, by thermal binding, by chemical binding and/orby mechanical needling.
 7. The method as claimed in claim 1,characterized in that the mat is a mat of filaments coming from amachine in hot-melt operation or a mat of fibers coming from a card fornonwoven fabrics or from a machine operating by air, known as air-laidoperation.
 8. The method as claimed in claim 1, wherein the step ofreducing the displacement speed includes reducing the displacement speedin an amount sufficient to reduce the ratio of a property of thenonwoven fabric in the length direction and the breadth direction.
 9. Amachine for producing a nonwoven fabric, comprising a first element fordelivering a mat to means for compacting it in the direction ofthickness, characterized in that said means are also means for reducingthe displacement speed of the mat at the point where it is compacted,further including consolidating means for consolidating the mat, theconsolidating means being arranged downstream of the compacting means inthe direction of displacement of the mat, and vacuum means formaintaining the mat between the compacting means and the consolidationmeans by a vacuum.
 10. The machine as claimed in claim 9, characterizedin that the compacting and speed reduction means are implemented by theformation of a nipping point between the first element and anothermoveable element having a linear speed lower than that of the firstelement.
 11. The machine as claimed in claim 10, characterized in thatthe other moveable element is a conveyor or a cylinder.
 12. The machineas claimed in claim 9, characterized by means intended for wetting themat when it is being compacted or when it has just been compacted. 13.The machine as claimed in claim 9, characterized in that theconsolidation means are arranged so as to consolidate the mat when itpasses over another moveable element.
 14. A method for producing anonwoven fabric including a mat of organic filaments or organic fiberscomprising the steps of providing a first movable element operable at afirst linear speed for transporting the mat along a displacement pathand another movable element operable at another linear speed for furthertransporting the mat along the displacement path, forming a nippingpoint between the first movable element and the another movable element,the another movable element being arranged above the first movableelement, transporting the mat at a displacement speed along thedisplacement path and through the nipping point, compacting the mat inthe direction of thickness in the nipping point and reducing thedisplacement speed of the mat in the nipping point by operating theanother movable element at a linear speed that is from about 5% to about50% lower than that of the first movable element, consolidating thecompacted mat at a downstream consolidation station to form aconsolidated mat, and wetting the mat at compacting or just downstreamof compacting.